Spark-plug



H. E. CLEMONS.

SPARK PLUG.

APPLICATION FILED MAY 25, I918.

' Patented Nov. 22, 1921 PATENT OFFICE.

HERMON E. CLEMONS, OF PULASKI, NEW YORK.

SPARK-PLUG.

To all whom it may concern:

Be it known that I, HEnMoN E. GLEMONB, a citizen of the United States, residing at Pulaski, in the county of Oswego and State of New York, have invented certain new and useful Improvements in a Spark-Plug, of which the following is a specification.

This invention relates to new and useful improvementsin spark plugs and the rimary objectof the invention is to provi e a new and improved type of spark plug that has means for utilizing the heat generated during the operation of the engine, to keep the electrodes of the plug free from carbon deposits, and hence, increasing the efficiency and durability of an article of this character.

Another object of the invention is to pro vide a device of this character which is easily and simply constructed, inexpensive to manufacture, and one which will be very efiicient in operation.

\Vith these and numerous other objects in view, my invention consists of the novel features of construction, combination and arrangement of parts which will be herein referred to and more particularly pointed out in the specification and claims.

In the accompanying drawings:

Figure 1 is a vertical section through the spark plug,

Fig. 2 is a bottom plan view thereof,

F ig. 3 is a side elevation of the tubular terminal member that forms the heat retaining casing, and

Fig. 4 is a side elevation of the washer that retains: the above mentioned member in position. i

In describing my invention, I shall refer to the drawings in which similar reference characters designate corresponding parts throughout the several views.

The numeral 1 designates an open ended. outer casing which is provided with external.

'threads 2 on its lower outer end and the upper end thereof ,is provided withan in: wardly projecting flange 3 for a purpose which will be hereinafter more fully described. The casing has mounted therethrough a non-conducting bushing .4 that is preferably formed of porcelain and which has one portion thereof designated by the numeral 5 projecting through the upper end of said casing.

Specification of Letters Patent.

Patented Nov. 22, 1921.

Application filed Kay 25, 1918. Serial No. 236,543.

The non-conducting bushing is providedwith an enlarged portion 6 disposed within the casing 1 adjacent its upper end, and the shoulder formed by the enlarged portion is adapted to bear against flange 3 at the upper end of said casing, saidlparts being separated by a gasket57 as clearly shown in Fig.1 of the drawings. The bushing 4 has positioned therethrough the central electrode or conductor of the pin which is designated by the numeral 8, sai electrode proecting from the upper end of the bushing, and having the conventional type of jam nut positioned on the upper end that is adapted to bear against a compression nut lOth-at is disposed on the upper end of said bushing. The opposite end of the electrode projects from the portion of the bushing disposed within the casing 1, and through said casing to a point beyond the'lower end thereof as is clearly shown in Fig. 1 of the draw ings. The electrode is provided with an enlarged portion'll that is positioned Within a recess 12formed' in the lower end of the bushing, for the purpose of which is ob- VlOllS.

The heat retaining means that forms the improvement of this spark plug comprises a tube shaped secondary terminal 13, that is provided with an outwardly flared open 11 per end 14, said tube being adapted to e positioned up through the lower end of the casing 1, and spaced from the inner wall thereof and having the flanged portion 14.

bear against the lower shoulder of the enlarged portion 6 of the bushing. The tubular terminal will surroundthe lower end of the bushing and likewise the projecting portion of the electrode 8. This tubular terminal is held in position by an externally threaded washer member 15 that is adapted for cooperative engagement with internal threads on the inner face of the casing ad .jacent the lower shoulder of the enlarged portion of the bushing, said washer bearmg against the outer face of the flared portion 14 at the upper end of the tubular member, and adapted to hold thesame against the lower shoulder of the bushing, as clearly shown in Fig. '1 of the drawings. The lower edge of the washer 15 is notched as shown at 16 so as to facilitate the placing or removing of the washer in operatlve position.

The lower end of the tubular terminal 13 extends inwardly as shown at 17, and up-: wardly so that it surrounds the terminal 8 adjacent the lower extremity thereof. This forms an opening through which the terminal is positioned, and the edges of the opening are disposed in close proximity to the terminal, so that a spark gap is formed between these parts. The lower end of the tubular terminal is provided with a plurality of slits 18 preferably three in number, for a purpose to be hereinafter more fully described.

In operation, when thevarious parts of the spark plug are disposed as is clearly shown in Fig. 1 of thedrawings, upon the current passing down the electrode 8 it will cross the gap between the secondary terminal 13 formed at the lower contracted end thereof, and up through said terminal out to the casing 1 as is-obvious. Obviously, the passage of the heated gases through the tubular terminal will heat the same. The heated gases passing down through the slotted lower end of the member will heat the lower portion of the plug and consequently will prevent the formation of carbon deposits between the terminals. The-space between the lower terminal and'the wall of the tubular secondary terminal will form a heat chamber that will carry out the objects above described. The washer member 15 that holds the tubular terminal as well as the bushing within the casing of the spark plug. owing to the fact that it requires a specia tool for assembling or taking apart the plug, prevents the likelihood of the plug being damaged by unskilled hands, as where an external packing nut is used, and a hammer and wrench are used to take the plug apart, which would be likely to damage the insulating bushing. This type of washer member requires a special tool that is engageable with the notched lower edge thereof to remove the washer or place the same in position.

From the foregoing descriptiontaken in connection with the accompanying drawing, it is thought that a clear and comprehensive understanding of the construction, operation and advantages of my invention may 'be had, and while Ihave shown and described the device as embodying aspecific structure, I desire that it be understood that such changes may be made in said structure as do not depart from the spirit and scope of the invention as claimed.

Havin fully described my invention, what I c aim as new, and desire tosecure by Letters Patent, is:

A spark plug comprising an open casing,

a non-conducting bushing projecting from one terminal of the casing having an enlarged portion confined within the casing, a center electrode carried, by the bushing, a tubular member positioned within the lower end of the casing and spaced from the inner wall thereof and having an outwardly directed flange at its upper terminal bearing against the enlarged portion of the bushing andconstituting a asket therefor, a washer screw threaded 1n the casin and bearing against the flared terminal of t e tubular member to hold the latter and the bushing in position, notches formed on said washer for removing the same from the casing, and thereby releasing the tubular member, and inwardly directed integral fingers carried by the tubular member terminating in spaced relation to the center electrode to provide 'a spark gap.

In testimony whereof I aiiix my signature.

hereto.

HERMON E. CLEMONS. 

